add unit tests for initSelector options

[scottjehl]

Many widgets now have initSelector options that need testing. (263193f)

I think we can just append an element with some obscure classname, then change the initSelector to match that classname, and trigger "create" on the parent element to make sure it inits.

[toddparker]

Closing as a dev task. Tracked here:
https://github.com/jquery/jquery-mobile/wiki/Dev-tasks